Constipation, Witholding, Overflow - Bowel Problems & Autism
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Toilet Training Difficulties for those with ASD Autism

Constipation, Witholding and Overflow – A Deeper Dive into Bowel Problems for Individuals with ASD

The article that I wrote June 2019 on fecal smearing has generated a lot of mail and comments over the past year. When it comes to toileting difficulties, many challenges center around bowel movements and these 3 occurrences – constipation, withholding of the stool, and overflow. All three of these problems can be a cause of fecal smearing. Let’s have a look at each one of these problems.


Constipation is the most common bowel problem among individuals with autism. About 5 – 30% of children in general experience constipation. It is important to seek medical advice for constipation because there could be an underlying medical cause. Signs of a medical problem are a history of constipation since birth, weakness in the lower limbs, and abdominal distension with vomiting.

Most children who are constipated tend to be healthy. Increasing fiber in the diet alone will not make constipation go away without adequate fluid intake. When a person is constipated, the large bowel becomes distended, but there is a lack of awareness that the bowel is full. The sense of feeling this is called interoceptive awareness. Receptors located throughout the inside or our body, in our organs, muscles, skin, bones gather information from the inside of our body and send it to brain. People with autism tend to have impairment in this area. This means the signal of a full bladder or needing to eliminate does not reach the brain so there is no impetus to get to the toilet or the sensation of needing to go is felt too late (a full bladder to the point of bursting). There are things you can do to increase a person’s body awareness and the feeling of the need to “go”. Kelly Mahler, an OT who has done extensive work in the area of interoception and autism, gave an excellent webinar on this topic if you would like to dive deeper into this important topic.

The problem with constipation is the longer poop stays inside the bowel, the harder it gets and becomes more painful to pass. This can become a viscous cycle because the child will do everything they can to avoid the pain of pooping. This painful elimination memory can stay with children for years, even after the problem is fixed.

potty training in bathroom

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Signs of Constipation

Keep an elimination journal to become aware of the following signs of constipation:

  1. Fewer than 3 complete stools a week
  2. Small hard balls that look like rabbit droppings
  3. Huge poops that happen occasionally and can block the toilet
  4. Poor appetite and irritability that improves after a bowel movement
  5. Abdominal pain and/or discomfort
  6. Posturing that demonstrates poop is being held such as walking with straight legs, tiptoes and arched back
  7. Straining when trying to poop (although this is not always a sign of constipation)
  8. Anal pain and bleeding when passing stool

Factors That May Contribute to Constipation

  • Low fiber diet (but a high fiber diet won’t help unless there is good fluid intake along with the fiber)
  • Inadequate fluids
  • Witholding the bowel movement
  • Anxiety around the toilet (thinking something may be lurking in there like a monster or snakes)
  • Mitochondrial dysfunction
  • Gut Dysbiosis
  • Food allergies or sensitivities
  • Sensory issues
  • Lack of interoceptive awareness
  • Ingrained thinking that poop goes into a diaper and not into the toilet
  • Dislike of change – moving from the diaper to the toilet
  • Anxiety around a new situation such as going to school
  • Can’t generalize the toileting skill in order to use different toilets

Treating Constipation

Constipation treatment is done in two stages: disimpaction to clear the blockage and then a maintenance protocol to prevent a recurrence of constipation. Some parents don’t like the thought of using medications, but if the large bowel is continually stretched by constipation it can lose motility. There is an excellent chart of constipation treatments outlining the advantages and disadvantages of each on pages 125 – 127 in the book Toilet Training and the Autism Spectrum (ASD) – A Guide for Professionals.

Other things to try:

  • Relaxing the muscles. Try blowing bubbles or blowing a blow toy like a pop bottle whistle.
  • Increase fluid intake. Have a water around in several places. My children will drink if water is left near them but won’t get a drink on their own steam. (This is an interoception problem, not knowing when they are thirsty.)
  • Limit processed foods and lean towards a high fiber diet accompanied by adequate fluid intake.
  • Explore elimination positions. Make sure a child is stable on the toilet and not having to balance to stay on.
  • If a child likes to squat to poop, consider the Squatty Potty.
  • Read stories about pooping such as It Hurts When I Poop! A Story for Children Who Are Scared to Use the Potty, A Feel Better Book for Little Poopers.
  • Create a social story specific to the child’s needs.


Constipation is associated with witholding the bowel movement because if it is uncomfortable and difficult to pass a stool, a person can become fearful of pooping. A painful experience will not want to be repeated. In order to avoid pooping, the body signals may be ignored.

Witholding is also connected to anxiety. There can be anxiety around using different toilets, not being able to use a diaper, not being able to use a certain elimination position when using the toilet, and fear of being splashed or not understanding the sensations around pooping.

To address the problems around witholding, refer back to the constipation section because once constipation is addressed, the witholding often stops.

Overflow Soiling

Overflow soiling is connected to constipation. When the rectum is full and not emptying, loose stool from higher up in the large bowel leaks out from around the constipated area. This leakage can be mistaken for diarrhea. The difference between this and a stomach bug is the child feels well and is eating without any vomiting.

Leaking happens without any control or choice in the matter. The child feels the leakage after it happens. Remember, when the bowel wall has been stretched repeatedly from constipation, the sensation of a full bowel isn’t felt. Address overflow issues by reading the constipation section as the two are connected.

Final Thoughts

While toileting difficulties can try one’s patience, it’s important to understand that there are reasons for these problems and the child is not in control of them. Seek medical help if toileting problems are persistent. Share articles like this one with your doctor because having ASD presents specific toileting concerns that the general public may not have. I was able to share a lot of information with my pediatrician that was new to him through my own research concerning my son’s toileting issues.

Bowel problems can improve over time with maturity and understanding how to intervene when problems like constipation arise. We still struggle with this issue and my son is now in his twenties. The difference is I now understand what the problem is and can address it when I see the signs of constipation such as fecal smearing.

To learn more about toileting training difficulties, access our toileting webinar.



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  1. Leesa Schilling, Occupational Therapist says:

    Thank you very much, Maureen! This is a great resource and I’m sure I will be pulling it out frequently.

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